Kilns

ABSTRACT

A drum kiln is provided for treating ores and like materials for preheating and prereduction which kiln includes an elongated cylinder journalled for rotation with its axis inclined to the horizontal, means for rotating said cylinder to-and-fro through an angle less than 360* and a port in the wall of said cylinder intermediate its ends and position so that the material in the cylinder does not contact it, said port selectively admitting and discharging solids and gases into the cylinder.

14 1 Sept. 11,1973

United States Patent Kocks Meyer et a m t m n" 1 ya etnn" flue-uh" e aa memm Hfle .m eee ZMHHR 235923 666675 999999 111111 574928 425000 0072700 817946 Friedrich Kocks, Freiligrathstrasse 1,

Primary Examiner-Gerald A. Dost Att0rney-Buell, Blenko, & Ziesenheim P 20 57 57 ABSTRACT 266/18 A drum kiln is provided for treating ores and like matez 1 rials for preheating and prereduction which kiln in- 266/18, 20 24 36 cludes an elongated cylinder journalled for rotation 7 5 /33 39 with its axis inclined to the horizontal ing said cylinder to 360 [21] Appl. No.: 197,423

[30] Foreign Application Priority Data Nov. 25, 1970 Germany..

[51] Int.

[58] Field of Search means for rotat- -and-fro through anlangle less than References Ci and a port in the wall of said cylinder intermediate UNITED STATES PATENTS its ends and position so that the material in the c ylmder does not contact it, said port selectively admitting and 8/197] 266/36 H discharging Solids and gases into the cylinder.

8/1967 Harada............. 266/20 1/1966 Schenck et a1. 75/34 16 Claims, 4 Drawing Figures PATENTEB SEPl 1 I973 SHiET 2 BF 3 IN VE N TOR av 0 M KILNS purity are smelted for preheating the iron ores mixed with reducing agents to a temperature above 1,000C and/or prereducing the mixture. The gas-fired or oilfired rotary kilns operate mostly by the countercurrent process, the waste gases being sometimes used for the heating of the rotary kiln.

By the partial degradation of the oxygen in the preheated ore prior to the charging to the electrical furnace, the expenditure in electrical energy can be considerably reduced and at the same time the production of the furnace increased. The higher the degree of reduction achieved in the rotary kiln, the more is it possible to lower the current consumption in the subsequent steelmaking in the electrical furnace. To achieve an optimum reduction it is necessary to maintain certain compositions of the material to be reduced and of the furnace atmosphere and certain temperatures inthe different sections of the kiln. Owing to the great lengths of the kiln, however, the control of the said parameters causes considerable difficulties.

For the control of the composition of the material to be reduced it is known for example that fine-grained ore or reducing carbon can be added at one or more points of the kiln. Since the kiln should rotate as con tinuously as possible, the introduction of the materials through the moving kiln wall causes considerable diffrculties and can be made possible only at a considerable expenditure in equipment.

It is a feature of the invention to provide a drum kiln wherein the optimum conditions of reduction can be adjusted in a simple manner and at low expenditure in equipment.

In accordance with the present invention, a drum kiln comprises a cylinder mounted so that it moves to-andfro about its axis through an angle less than 360 and is adjustable as a function of the degree of filling of the kiln in such a manner that a part of the wall of the cylinder does not come into contact with the material to be treated, and the port for additional material and/or gases in provided in the part of the the cylinder wall that remains free.

When solid or liquid additional materials are to be introduced into the drum kiln, the port appropriately penetrates the kiln wall and can be closed.

By way of example, a stationarytube segment may be provided as a closure for the port, such segment concentrically and snugly surrounding the cylinder, and ex- A closable feed funnel may be provided directly above the port for the introduction of the extra charge, the end of the funnel being sealingly connected through a nozzle to the port.

For the introduction of the extra charge, the port in the cylinder wall can alternatively be connected to 'swingingly hinged pipelines.

Furthermore, a duct may be provided on the outside of the cylinder, parallel to the cylinder axis, to connect the port to feed means for the extra charge disposed at the inlet end of the cylinder. The duct opening located at the inlet end of the cylinder may be connected in at least one position of the cylinder to a container contending at least over the range of angular displacement of the port determined by the to-and-fro movement,

the tube segment being provided in its upper region with an opening, which at the to-and-fro motion of the cylinder in a certain position or region coincides with the port of the latter. The closure may also be a flap which is attached pivotably at the edge of the port.

taining the extra charge materials, whilst it is closed in the other positions of the cylinder.

The actuation of all closure elements is appropriately controllable by the cylinder movement, so that the opening and closing takes place automatically as a function of the angular position of the cylinder. For the feed of treatment gases or for the extraction of waste gases a port may be provided at a certain point in the cylinder wall, which port is in communication with a gas feed or vent" in every angular position of the cylinder. The cylinder may be surrounded in the region of its gas port by a stationary tube segment which embraces the cylinder concentrically and snugly and which is provided with a slot over the entire to-and-fro range of the gas port in the cylinder wall, the tube segment being sealingly surrounded by a shroud which connects the slot to a feed or vent line;

Since in the drum kiln in accordance with the invention the material to be treated does not come into contact with the ports provided in the cylinder wall, sealing problems do not arise, so that is also possible to treat a molten charge in the drum kiln. In addition to suitable devices for the feed of the molten metal and an appropriate brick-lining the cylinder has at its outlet end and indrawn lip so that the molten metal can collect at the lower end of the kiln and, at appropriate further feed, can pass over the indrawn lip via an appropriate line for example into an electrical furnace.

When operation is to be interrupted, the molten metai, which has accumulated on the indrawn lip, has to be drawn off. For this purpose a segment, or several segments, of the lip may .be detachable, so that the molten metal can flow off through the gap soformed.

The invention will now be further described, by way of example, with reference to the accompanying drawings, in which:

FIG. 1 is a longitudinal section through one embodiment of drum kiln in accordance with the invention;

FIG. 2 is a section along the line II-II of FIG. 1; FIG. 3is a section along the line III--III ofFIG. l; and I FIG. 4 is a longitudinal section through another embodiment of drum kiln in accordance with the invention.

Referring to FIG. 1, a drum kiln comprises a cylinder 2 whose axis is slightly inclined to the horizontal. On the higher end 4 of the drum kiln 2 is a chargingdevice 6 by means of which the material to be roasted is introduced into the drum kiln. The material to be roasted passes gradually through the drum kiln and may be subjected therein to various treatments before it reaches the outlet end 8 whence it is passed, for example, to an device 10.

The transport of the material to be roasted takes place by virtue of the inclination of the cylinder and also of a to-and-fro rotary movement which the cylinder performs about its axis. To accomplish the to-andfro movement, the cylinder 2 is provided with annular runners 12 which are guided by reversibly drivable rollers l4.

. Burners 16 are provided at various points in the cylinder 2 for heating the material to be roasted. For additional heating, it is also possible to use, for example, the waste gases of an electrical furnace installed downstream.

To achieve optimum results of the treatment it is necessary in many cases to introduce extra charges into the drum kiln at points remote from the input end. For this purpose the cylinder 2 is provided with a port 18 through which the corresponding extra charges, for example fine grained ore, reducing carbon etc. can be introduced. Naturally, more than one port, arranged over the length of the furnace, may also be provided.

The port 18 is arranged in a region-of the periphery of the cylinder which does not come into contact with the material to be treated. The cylinder 2, which is mounted so that it can move to-and-fro about its axis performs during its operation through an angle which is smaller than 360 and which is so adjusted in relation to'the degree of filling that the material to be treated remains at a'safe distance from the port 18.

The extra charges are introduced through the port 18 into the inside of the kiln only during brief periods, whilst during the remaining time the port is closed, so as not to affect detrimentally the temperature gradient in the kiln. As shown in FIGS. 1 and 2, a stationary tube segment 20 is provided as a closure of the port 18, and concentrically and snugly surrounds the cylinder 2 and covers the port 18 over its entire movement range. In its upper region the tube segment 20 has an opening 22, with which the port 18, provided in the cylinder 2, registers in its topmost position. Above the opening 22 provided in the tube segment 20 is a feed funnel 24 through which the extra charges, at suitable relative position of the openings 18 and 22 to one another, can

pass into the interior of the cylinder 2. To avoid any unnecessary escape of gas, the opening 22 is connected via a nozzle 26 tightly to the end of the feed funnel 24. The bottom end of the feed funnel 24 can be closed by means of a shutter or a flap and can be opened at an appropriate position of the cylinder as a function of the movement of the cylinder.

Instead of the cover by the tube segment 20, the port 18 can alternatively be closed by a flap controllable by the movement of the cylinder. Furthermore swingingly hinged pipelines may be provided for the feed of the extra charges.

In some applications of the drum kiln it may be necessary for treatment gases and/or heating gases to be I introduced at different points into the cylinder 2. On the other hand it may be necessary to withdraw gases at various points of the drum kiln so as to allow operation at certain regions of the kiln in concurrent flow and in other regions in countercurrent flow.

To achieve a continuous gas feed and/or gas withdrawal,a port 28, as shown in FIGS. 1 and 3, is permanently in communications with a gas feed or vent. As shown, the cylinder 2 is surrounded in the region of its port 28 by a stationary tube segment 30 which embraces the cylinder concentrically and snugly. The tube segment 30 is provided with a slot 32 over the entire pivotal range of the port 28 so that the port 28 is not closed in any of its positions. gas-tight canopy 34 adjacent the tube segment 30 connects the slot 32 to a gas feed or a vent line 36.

The drive means (not shown) for the rollers 14 is adjustable so that the angle of the to-and-fro movement of the cylinder can be adjusted in accordance with the size of the charge in the cylinder so that the charge never comes into contact with those parts of the cylinder wall containing the ports 18 and 28.

In the embodiment represented in FIG. 4 of the drawings, a duct 38 is provided on the outside of a cylinder 2 parallel to the axis of the cylinder and is connected to a port 40 provided in the cylinder wall. The duct 38, in communicationwith the port 40, is chargeable via a container 42 at the input end, the extra charges introduced into the duct 38 being transported in the direction of the port 40 by virtue of the inclined arrangement of the cylinder and of the to-and-fro angular movement. The outlet end 44 of the container 42 is opened only when the inlet end of the duct 38 moves past it. In all other positions of the cylinder, the outlet end 44 of the container 42 is closed. The'opening and closing of the outlet opening 44 of container 42 may be brought about for example in that a cover plate (not shown in the drawing) is placed against the end face of the cylinder 2 and covers the container outlet 44 except when the outlet passes the mouth of the duct 38.

It is also possible to treat molten metal in a drum kiln in accordance with the invention in a continuous process and at the same time introduce extra charges at various points. Such an application is possible, because the molten material to be treated, owing to the to-andfro angular movement taking place only over a certain angle, does not come into contact with the ports provided in the cylinder wall.

To make it possible to retain the molten material to I be treated in the cylinder, the cylinder is provided at the outlet end with a lip 46 drawn inwards, on which the material can accumulate and pass over from there into a downstream vessel, for example an electrical furnace. For the complete emptying of the furnace a segment of the lip may be made detachable.

The drum kiln in accordance with the invention can be used for purposes other than the treatment of metals, such as for non-metal materials, e.g., cement and similar materials.

While I have illustrated and described certain preferred embodiments of my invention in the foregoing specification, it will be understood that this invention may be otherwise embodied within the scope of the following claims.

I claim: I

l. A drum kiln comprising an elongated cylinder journalled with its axis slightly inclined to the horizontal and having in its wall at least one port for introduction and removal of solids and gases provided in the region between its inlet end and outlet end, and means for turning the cylinder to-and-fro about its axis through an angle less than 360 and such that the part of the cylinder wall containing said at least one port does not come into contact with the material to be treated.

2. A kiln as claimed in claim 1 in which. the angle of to-and-fro movement'is adjustable as afunction of the degree of filling of the furnace.

3. A kiln as claimed in claim 1 in which said port for extra charges is closable, on each side of a predetermined addition point.

4. A kiln as claimed in claim 3, in which a stationary tube segment surrounds the cylinder concentrically and snugly and extends at least over the range of angular displacement of the port for closing said port except when an opening provided in the upper region of the tube segment is in registry with the port.

5. A kiln as claimed in claim 3, in which a swivellable flap is provided for closing the port.

6. A kiln as claimed in claim 4, in which a closable feed funnel for the extra charges isprovided directly above the port.

7. A kiln as claimed in claim 6, in which the end of the feed funnel is connected to the port sealingly via a nozzle.

8. A kiln as claimed in claim 1, in which the port in the cylinder wall is connected to a swingly hinged pipeline for the feed of extra charges.

9. A kiln as claimed in claim 1, in which a duct is provided on the outside of the cylinder parallel to the cylinder axis and connects the port to charging means at the input end of the cylinder.

10. A kiln as claimed in claim 9, in which the mouth of the duct located at the inlet end of the cylinder can be connected in at least one position of the cylinder to a container for containing extra charges, whilst it is closed in the remaining positions of the cylinder.

11. A kiln as claimed in claim 3, in which the actuating and closing elements are controllable by the movement of the cylinder.

12. A kiln as claimed in claim 1 which has at least one port in the cylinder wall, which port in any angular position of the cylinder is in connection with one of a gas feed and vent.

13. A kiln as claimed in claim 12 in which the cylinder wall in the region of its gas port is surrounded by a stationary tube segment, which embraces the cylinder concentrically and snugly and which is provided with a slot over the entire swinging range of the gas port and the tube segment is surrounded by a shroud which connects the slot to a one of a feed and vent line.

14. A kiln as claimed in claim 1, in which an inwardly drawn lip is provided on the outlet end of the cylinder.

15. A kiln as claimed in claim 14, in which the lip has at least one detachable segment.

16. A kiln as claimed in claim 14, further comprising means for feeding molten metal into the inlet end of .the

cylinder.

} TIITTTTD STATES TATTNT oTTTtT EERWWEATE Of CUEEECTlON Patent No. 3,758,089 Dated September 11, 1973 n fl Friedrich Kooks It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column 1, line 53, "in" first occurrence, should be -is-, same line, before "cylinder" delete the-.

Column 2, line 34, after "that" insert --it--.

Column 4, line 3, before "gas-tight" insert -A--.

Column 5, Claim 8, line 19, "swingly" should be --swingingly-.

Signed and sealed this 15th day of January 19724..

(SEAL) Attest:

EDWARD M.,FLETCHER,JR., RENE D." 'TEGTMEYER Attesting Officer Acting Commissioner of Patents FORM PO-1050 (10-59) USCQTMM-DC 50375-4 69 w u.s. sovzmmsm PRINTING 0mm; 1959 0-366-334, 

1. A drum kiln comprising an elongated cylinder journalled with its axis slightly inclined to the horizontal and having in its wall at least one port for introduction and removal of solids and gases provided in the region between its inlet end and outlet end, and means for turning the cylinder to-and-fro about its axis through an angle less than 360* and such that the part of the cylinder wall containing said at least one port does not come into contact with the material to be treated.
 2. A kiln as claimed in claim 1 in which the angle of to-and-fro movement is adjustable as a function of the degree of filling of the furnace.
 3. A kiln as claimed in claim 1 in which said port for extra charges is closable, on each side of a predetermined addition point.
 4. A kiln as claimed in claim 3, in which a stationary tube segment surrounds the cylinder concentrically and snugly and extends at least over the range of angular displacement of the port for closing said port except when an opening provided in the upper region of the tube segment is in registry with the port.
 5. A kiln as claimed in claim 3, in which a swivellable flap is provided for closing the port.
 6. A kiln as claimed in claim 4, in which a closable feed funnel for the extra charges is provided directly above the port.
 7. A kiln as claimed in claim 6, in which the end of the feed funnel is connected to the port sealingly via a nozzle.
 8. A kiln as claimed in claim 1, in which the port in the cylinder wall is connected to a swingly hinged pipeline for the feed of extra charges.
 9. A kiln as claimed in claim 1, in which a duct is provided on the outside of the cylinder parallel to the cylinder axis and connects the port to charging means at the input end of the cylinder.
 10. A kiln as claimed in claim 9, in which the mouth of the duct located at the inlet end of the cYlinder can be connected in at least one position of the cylinder to a container for containing extra charges, whilst it is closed in the remaining positions of the cylinder.
 11. A kiln as claimed in claim 3, in which the actuating and closing elements are controllable by the movement of the cylinder.
 12. A kiln as claimed in claim 1 which has at least one port in the cylinder wall, which port in any angular position of the cylinder is in connection with one of a gas feed and vent.
 13. A kiln as claimed in claim 12 in which the cylinder wall in the region of its gas port is surrounded by a stationary tube segment, which embraces the cylinder concentrically and snugly and which is provided with a slot over the entire swinging range of the gas port and the tube segment is surrounded by a shroud which connects the slot to a one of a feed and vent line.
 14. A kiln as claimed in claim 1, in which an inwardly drawn lip is provided on the outlet end of the cylinder.
 15. A kiln as claimed in claim 14, in which the lip has at least one detachable segment.
 16. A kiln as claimed in claim 14, further comprising means for feeding molten metal into the inlet end of the cylinder. 